fix: Rate limit timer was never created due to inverted logic

[rmdes]

Bug

The rate limit timer was never being created due to inverted logic in createLimitTimer():

// Before (broken)
if (!rateLimited) return;  // rateLimited is false, so !false = true, always returns!
rateLimited = true;        // Never reached

Impact

When hitting Bluesky's rate limit, the queue would:

• Log "Post rate limit exceeded - process will resume after 30 seconds"
• But the timer was never created
• Queue kept retrying every runInterval (60s) instead of respecting the rate limit
• This caused repeated failed attempts and wasted API calls

Fix

  // After (fixed)
  if (rateLimited) return;  // If already rate limited, don't create duplicate timer
  rateLimited = true;       // Now correctly sets the flag

Testing

Observed in production logs where a queue with 2791 items kept hitting rate limits every 60 seconds indefinitely, instead of properly backing off.